PINNED - Lithium battery conversion/info

[shirley_hkg]

Use in Alaska , ability to discharge in low temperature will be crucial .

Lithium Titanate Oxide battery is the candidate .

[Burgerman]

He may be correct. I know one case where a guy at my model heli club, put a fully charged helicopter with a 8Ah 10S lipo into his van in winter. The battery cooled. His battery went like a bomb as it did not hold that amount of watt hours when cold! So presumably it pushes volts high? So those things can be dangerous.

[wilsonintexas]

Short wish list / thoughts

Yes I'm in Alaska but the times this would be used is not one it's extremely cold

I now also have an RV and there is currently secondary deep cycle marine batteries to power the RV accessories

They last all nightpowering the furnace and a computer shooting time lapse photos

I also have plenty of storage compartment space in the RV

And I have plenty of space on the modified bicycle it's basically a big trach to melt battery pack anywhere I wanted


So my thought is building a battery pack that could possibly be reused in several configurations
1.would be 36 or even 48 volt for an electric bike

2. If I had that I might as well make it so I could reconfigure it in the 12 V parallel packs to power the RV auxiliary functions

That's for the batteries
For charging my thoughts are
One in the RV the alternator has very high output I know I can't use that to charge the batteries but I was hoping I could use it to feed the battery charger

When the RV is plugged in there is a very heavy 12 V transformer with circuit breaker I was hoping to be able to tap into that for charging while I'm traveling

Those are thoughts

Looking for
Battery cell reco
Charger reco

[wilsonintexas]

I know that I've talked about an electric chair for my daughter in the past

She's not really interested in it at this point

And at my dad's form that I recently inherited there is a chassis from a zero turn lawnmowe where the cutting deck got abused and has been removed

If I were thinking of anything for her I'm thinking that I might be able to put on larger tires and let her use something like that there's enough room to get a reclining seat and she has enough on her movement to be able to control the two warm controls that are currently already on the system

That would probably due for letting her run around the form and have a little bit of freedom when we go down there and if it worked out then we could look at bringing it up for outdoor city use

[Burgerman]

That's for the batteries
For charging my thoughts are
One in the RV the alternator has very high output I know I can't use that to charge the batteries but I was hoping I could use it to feed the battery charger

Of course you can. Thats its job. Its output is connected directly to the starter battery at least. Its high Amps, which is good, but its voltage is regulated to around 13.8 to 14.2 or 3 Volts. You can charge batteries directly. I do this daily. Unless you mean lithium in which case you need a PL8, and charge FROM the vehicle battery, engine at idle, at 40A.

[hensonshome]

I know its been several yrs. since this post was 1st started and was wondering how this setup works.
I'm not to savvy with this tech stuff so forgive me for some of the silly questions I ask.
I can fabricate just about anything but tech I can't do.
So look at this please and give me your opinion.
http://www.batteryspace.com/lifepo43812 ... arate.aspx

[Burgerman]

Thats 4x Headway 10Ah cells. That would be equal to 1/7th if one single 70Ah 12V battery.

You are doing what? Replacing a 70Ah grp 24 lead battery? You would need 7 of those or 14 to replace a pair. But that will only give you the same 70Ah as the lead bricks you throw away.

You need to be looking at 100Ah ish, or more to take full advantage of the benefits lithium can give you. That is a long life, and about 2 to 3 times the range. For eg, I replaced two 70Ah batteries with 120Ah here:
viewtopic.php?f=2&t=5380&start=160
and
viewtopic.php?f=2&t=5380&start=260

That will allow 3x the range, at least, and because they are only going to be charged every few days mostly, and will never be discharged deeply, and because the load on them is low because of the battery size, they should last a very long time. At least a decade.

[hensonshome]

Ok lm starting to understand that part of it now.
Thanks BM

[Gnomatic]

Door to door service to UK at £8
/kg

Hi Shirley. Have you been able to locate any couriers that are willing to ship to the US as well? I'd be interested in some of those cells, and I think expresso would be too if you can find a way to get them here. Thank you.

[shirley_hkg]

I'll go across the border myself , to see if any lower rate to UK / US .

Till the weather allows .

[snaker]

I ordered 17x75Ah cells (1 for spare), they will arrive in 1-2 weeks. Total cost (inc everything) is about $500.

[expresso]

I ordered 17x75Ah cells (1 for spare), they will arrive in 1-2 weeks. Total cost (inc everything) is about $500.

thats a great price - which cells did you order ? is that with shipping for you ?

[snaker]

They are in the link below. Yes, that cost is all I have to pay, includes all shipping/fee/tax. VN is beside China so shipping is easy and cheap.
https://item.taobao.com/item.htm?spm=a3 ... aobao_shop

[expresso]

thats great -

i wonder what they mean by this ?

please shoot before considering good, do not accept not to shoot, thank you!

[expresso]

thats great -

i wonder what they mean by this ?

please shoot before considering good, do not accept not to shoot, thank you!

[Burgerman]

I think if you don't want to accept them, you are meant to shoot the delivery driver.

[expresso]

[hotwheels_75]

You need to get creative.
Is it one single exactly "square" space?

My BM3 centre section is exactly 175mm wide, inside. 174 after powder coating.
That fits the width of the 12Ah cells, with plastic building blocks perfectly.

1mm less and it will not work. 1mm more and it will be able to move and rattle about. 175 gives a perfect fit to both the headway cells, the group 24 MKs, the PC1500 Odyssey, and to 3x 42Ah odyssey batteries on end.
.

I'm not sure if the headway 12ah batteries are going to fit my chair... thanks to a building error, my battery box is only 6.75 inches wide or 171.45mm. I've read conflicting info on the battery plus assembly blocks total size. I found a diagram which says With the blocks they're 6.72inches or 170.69mm & on http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm it says the lithium battery is exactly 171mm, but in the quoted post above 174mm is the bare minimum... Am I going to be able to squeeze them in there?

[Burgerman]

My guess just! I allowed room at 174 for a 1mm sheet of insulation material each side (its a ptfe sheet or rather something that feels like ptfe but black found in someones workshop) And mines about 174 inside. Yours will touch I think everywhere.

[hotwheels_75]

Only one way to find out.

Is it hard to change the layout or shape of the packs as shown in the diagrams from beginning of this topic? My box will hold 12 L x 5 H cleanly. I would have to use 56 though to make the 24v replacement? I might be able to do 64 with some rearranging of wires & connectors.if a layout of 4 stacks of 6 cells at one end with 8 stacks of 5 for the rest would work?

[expresso]

Only one way to find out.

Is it hard to change the layout or shape of the packs as shown in the diagrams from beginning of this topic? My box will hold 12 L x 5 H cleanly. I would have to use 56 though to make the 24v replacement? I might be able to do 64 with some rearranging of wires & connectors.if a layout of 4 stacks of 6 cells at one end with 8 stacks of 5 for the rest would work?

Unless your already committed to using the 12ah cells - have you considered using 15ah Cells ? something to think about - see if it may work out giving your space - you need 56 cells 15ah for 105ah pack - or 48 for 90ah pack -

i can only say for my Chair - the 12ah cells wasnt going to work for me - but the 15ah did work out fine - every chair setup is different - only you can know for sure if it can work for you -

[Burgerman]

You mean like this 120Ah pack?

download/file.php?id=4241&mode=view

download/file.php?id=4301&mode=view

download/file.php?id=4452&mode=view

download/file.php?id=4460&mode=view

download/file.php?id=4507&mode=view

The electricity doesn't care what route it takes. As long as cells are multiples of 8.

[hotwheels_75]

Unless your already committed to using the 12ah cells - have you considered using 15ah Cells ? something to think about - see if it may work out giving your space - you need 56 cells 15ah for 105ah pack - or 48 for 90ah pack -

i can only say for my Chair - the 12ah cells wasnt going to work for me - but the 15ah did work out fine - every chair setup is different - only you can know for sure if it can work for you -

The 15ah cells won't fit, I'll be lucky if the 12ah cells fit.

You mean like this 120Ah pack?


download/file.php?id=4452&mode=view

The electricity doesn't care what route it takes. As long as cells are multiples of 8.

Very similar to that one, I have a little more space in the rear of my box than the front. I "should" be able to fit 4 more cells on top of the rear of the pack to build a 64 cell pack. So that will give me 96ah? If that doesn't work I'll have to go with 56. I'm going to order 64 & hope for the best!

[Gnomatic]

The 15ah cells won't fit, I'll be lucky if the 12ah cells fit.

Even if you aligned the 15Ah Headway cells vertically?

24 of the 15Ah Headway cells aligned vertically(4cell x 6cell) in a pack fit within the footprint of a single Group 24 battery, with the Headway pack being shorter. Two Headway packs like this, one for each battery box, is good for 24v 90Ah in a chair.

[hotwheels_75]

The 15ah cells won't fit, I'll be lucky if the 12ah cells fit.

Even if you aligned the 15Ah Headway cells vertically?

24 of the 15Ah Headway cells aligned vertically(4cell x 6cell) in a pack fit within the footprint of a single Group 24 battery, with the Headway pack being shorter. Two Headway packs like this, one for each battery box, is good for 24v 90Ah in a chair.

Oh, yes, I guess that is an option! I'll have to think about my options. 64 12ah or 48 15ah cells.

[hotwheels_75]

Is there any benefit to going with 48 15ah cells in 90ah pack vs 64 12ah cells in a 96ah pack?
15ah cells installed vertically is definitely a space saver, I'd have nearly 1/2" of extra space in width & plenty of top clearance.

12ah cell pack will fill up entire battery compartment but will gain 6ah.

Either have any significant benefits over the other besides that?

[expresso]

i would say no big deal - 6ah extra really isnt alot - wont notice any difference between 90ah vs 96ah

for some reason - it just seems - for most of US - using 15ah Cells makes a difference - as with 12ah Cells - seems to come up short or too tight

[Burgerman]

The difference is 7 and a half percent capacity or range. Say 3 miles extra. Or if you prefer 3 miles of capacity not used every day. Which is good for the battery. Which is why its always best to go large...

[expresso]

i guess - always better to have more - i even added 30ah more to my 105ah -

but i found it hard to get 12ah cells in my chair -

[hotwheels_75]

Appreciate the suggestions, but guess I'll go with the 96ah pack, squeeze in every ah I can.